CN102189212A - Large-scale crank shaft bending forging die - Google Patents

Abstract

A large-scale crankshaft bending and forging forming die, the die has a channel steel-shaped main body composed of a horizontal base and two vertical side plates whose lower ends are fixed on it, and ribs connected to it are respectively provided outside the two side plates, Two baffle plates connecting the two side plates are respectively arranged at the two ends of the two side plates of the above-mentioned concave mold. The upper edge of the baffle is slightly higher than the contact surface between the lower end of the bending die and the blank. The overall height of the baffle is greater than the maximum stroke of the bending die. Although the present invention is simple in structure and easy to install, it can prevent the metal at the root of the crank arm from flowing to both sides of the crank throw, reduce the widening of the side of the crank arm and the depression on the side of the crank pin, and basically eliminate the depression at the root of the crank arm. To a certain extent, the forming quality and material utilization rate of forgings are improved.

Description

A large crankshaft bending forging die

Technical Field The present invention relates to a forging die, especially a large crankshaft bending forging die.

Background technology The crankshaft is one of the key parts in the engine, which is widely used in locomotive and ship engines. Most of the forged steel crankshafts used in large marine low-speed high-horsepower diesel engines are semi-combined crankshafts, except for a small number of small-bore low-speed integral crankshafts. The semi-combined crankshaft is composed of free end journal, output end journal, middle main journal and crank throw. The first three parts are simple in shape and small in size, while the crank throw is complex in shape and large in size, which is the key to crankshaft production. In a sense, the key technology of semi-combined crankshaft manufacturing is the forging and forming technology of the crank throw blank. For the free forging of a single large crank throw, there are mainly block forging method, ring forging method, upsetting forging method, die forging method, bending forging method and so on. Among them, the deformation process of the bending forging method is that the steel ingot is first pressed into a slab, then rough forged, and then bent and flattened in turn. Compared with the above-mentioned forming methods, this method has simple dies, small forming force, low requirements on equipment, and ideal metal flow line. Therefore, the bending forging method is widely used in the manufacture of semi-combined crankshafts. However, there are certain deficiencies: after the crankshaft is bent and forged, there are generally defects such as a large amount of widening of the side of the crank arm, and obvious depressions on the side of the crank pin and the root of the crank arm. The existence of these defects affects the forming quality of the forging, and it is not easy to guarantee the forging. size requirements. The size of the groove on the upper surface of the blank, the fillet on the side, the width of the opening of the die, and the size of the fillet of the die have a certain influence on the forming of the crankshaft. In the previous bending and forging forming, most of the forming defects were reduced by coordinating the relationship between these factors. However, through finite element simulation research, it is found that changing the shape of the blank and the size parameters of the mold have no obvious improvement on the above defects. In order to ensure the final forming requirements of forgings, in many cases, the machining allowance can only be increased to reduce defects, which not only greatly increases the production cycle, but also causes waste of materials.

SUMMARY OF THE INVENTION The object of the present invention is to provide a large crankshaft bending and forging die with simple structure, convenient installation and effective reduction of defects after crankshaft bending and forging. The present invention mainly adds two baffle plates on both sides of the existing die. The existing crankshaft bending and forging die is a channel-shaped main body composed of a horizontal base and two vertical side plates whose lower ends are fixed on it, and ribs connected to it are respectively provided outside the two side plates. Two baffles connecting the two side plates are respectively provided at the two ends of the two side plates of the above-mentioned concave die. The billet flows outward. The overall height of the baffle should be greater than the maximum stroke of the bending die, that is, after the bending stroke ends, the lower edge of the baffle is still below the contact surface between the lower end of the bending die and the blank. Leave a little gap between the baffle and the blank to facilitate unloading. The above-mentioned baffles can be fixedly connected with the side panels, or can be flexibly connected by fasteners.

When the blank is bent and formed, the metal flows along the lateral direction due to the effect of the side baffle, where the metal flows along the inner surface of the baffle to the crotch at the root of the crank arm with less resistance. As the deformation progresses, the metal builds up at the crotch opening at the root of the crank arm. This part of metal fills the defect in the crotch opening at the root of the crank arm, so that the size of the crotch opening can meet the size requirements of the forging.

Compared with the prior art, the present invention has the following advantages: although the present invention is simple in structure and easy to install, it can prevent the metal at the root of the crank arm from flowing to both sides of the crank throw, and reduce the widening of the crank arm side and the depression on the crank pin side , so that the amount of depression at the root of the crank arm is basically eliminated, and the forming quality and material utilization rate of the forging are improved to a certain extent.

Description of drawings

Fig. 1 is a schematic top view of the die of the present invention.

Fig. 2 is A-A view of Fig. 1 .

Fig. 3 is a schematic side view of the die of the present invention.

Fig. 4 is a schematic front view of the working state of the die of the present invention.

Fig. 5a is a schematic front view of the forging of the present invention.

Fig. 5b is a schematic side view of the forging of the present invention.

Fig. 6a is a detection diagram of the amount of depression inside the bellcrank crank arm processed by the existing mold.

Fig. 6b is a detection diagram of the amount of depression inside the crank arm of the mold processed by the mold of the present invention.

Fig. 7a is a detection diagram of the side widening amount of the crank throw processed by the existing mold.

Fig. 7b is a detection diagram of the widening amount of the side of the crank throw processed by the mold of the present invention.

Figure 8a is a detection diagram of the amount of depression on the side of the bellcrank pin processed by the existing mold.

Fig. 8b is a detection diagram of the concave amount of the bellcrank pin side surface processed by the mold of the present invention.

Detailed ways

In the schematic diagrams of the large crankshaft bending and forging die shown in Fig. 1, Fig. 2 and Fig. 3, the die has a channel-shaped main body composed of a horizontal base 1 and two vertical side plates 2 fixed on it at the lower end. Ribs 3 connected thereto are respectively provided outside the side panels. Two baffle plates 4 connecting the two side plates are respectively arranged at the two ends of the two side plates of the above-mentioned concave mold. The above-mentioned baffle plate is movably connected with the side plate through the fastener 5 . In the schematic front view of the working state of the die of the present invention shown in Figure 4, when the blank 6 is bent and formed, the blank is placed on the upper opening of the above-mentioned die, the bending die 7 is placed on the blank, and the upper edge of the baffle is slightly higher At the contact surface between the lower end of the bending die and the blank, the overall height of the baffle is greater than the maximum stroke of the bending die, that is, after the bending stroke is completed, the lower edge of the baffle is still below the contact surface between the lower end of the bending die and the blank. Leave a little gap between the baffle and the blank. The final forging 8 of the present invention is shown in Figure 5a and Figure 5b. Figure 6a is a detection diagram of the amount of depression inside the bell crank arm processed by the existing mold. In the figure, the dark color inside the crank arm is the sunken area, and it can be seen from the figure that the sunken amount is relatively large. Fig. 6b is a detection diagram of the amount of depression inside the bellcrank crank arm processed by the mold of the present invention. There is basically no dark sunken area inside the crank crank arm, and the inside depression of the crank arm is basically eliminated. Figure 7a is a detection diagram of the side widening of the crank throw processed by the existing mold, and the side widening is 1016.33 mm. Fig. 7b is a detection diagram of the side widening of the crank throw processed by the mold of the present invention, and the side widening is 961.72 mm, which is much less than that without a baffle. Figure 8a is a detection diagram of the amount of depression on the side of the bellcrank pin processed by the existing mold. The dark area in the figure is the depression of the bellcrank pin, and it can be seen from the figure that the amount of depression is relatively large. Fig. 8b is a detection diagram of the amount of depression on the side of the bellcrank pin processed by the mold of the present invention, from which it can be seen that the amount of depression is significantly reduced.

Claims (4)

1. a large-scale bent axle is bent forging mould, the channel steel shape main body that the two vertical side plates that this die is fixed thereon by base and lower end by level are formed, be respectively equipped with coupled gusset in the biside plate outside, it is characterized in that: be respectively equipped with two baffle plates that biside plate is linked to each other at the two ends of two side plates of above-mentioned die.

2. large-scale bent axle according to claim 1 is bent forging mould, it is characterized in that: the contact-making surface of baffle plate top edge a little higher than bending die lower end and blank.

3. large-scale bent axle according to claim 1 and 2 is bent forging mould, and it is characterized in that: the whole height of baffle plate is greater than the range of bending die.

4. large-scale bent axle according to claim 3 is bent forging mould, it is characterized in that: above-mentioned baffle plate flexibly connects by securing member and side plate.

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